JP2703725B2 - Cold forging tool - Google Patents
Cold forging toolInfo
- Publication number
- JP2703725B2 JP2703725B2 JP11277894A JP11277894A JP2703725B2 JP 2703725 B2 JP2703725 B2 JP 2703725B2 JP 11277894 A JP11277894 A JP 11277894A JP 11277894 A JP11277894 A JP 11277894A JP 2703725 B2 JP2703725 B2 JP 2703725B2
- Authority
- JP
- Japan
- Prior art keywords
- nib
- hole
- cold forging
- concave portion
- shape
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Landscapes
- Forging (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、四角又は六角等の多角
形に形成されるボルト頭又はナットブランクといった機
械要素ブランクを冷間圧造するための冷間圧造工具に関
する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cold forging tool for cold forging a machine element blank such as a bolt head or a nut blank formed in a polygonal shape such as a square or a hexagon.
【０００２】[0002]
【従来の技術】従来、ナットブランク等を冷間圧造する
ための冷間圧造工具は、図Ｘ１に示すように、第１のニ
ブ１０１と第２のニブ１０３とを重ねてダイスケース１
０５に嵌入した構造にされ、第１のニブ１０１のピン孔
１０７をエジェクターピン１０９で塞いで形成される凹
部１１１と、第２のニブ１０３に形成された六角形の貫
通孔１１３とによって、ナットブランクの形状をなす成
形孔を形成していた。なお、例示した冷間圧造工具はフ
ランジナット用で、フランジ部分を形成するために、貫
通孔１１３の図示上端側の開口１１５は鍔状に広がって
いる。2. Description of the Related Art Conventionally, as shown in FIG. X1, a cold forging tool for cold forging a nut blank or the like is composed of a first nib 101 and a second nib 103 which are overlapped with each other.
05, the pin hole 107 of the first nib 101 is closed by an ejector pin 109, and a hexagonal through hole 113 formed in the second nib 103 forms a nut. A forming hole in the shape of a blank was formed. The illustrated cold forging tool is for a flange nut, and the opening 115 on the upper end side in the drawing of the through hole 113 is formed in a flange shape in order to form a flange portion.
【０００３】ところで、ボルト頭やナットブランクは、
一般に頂面周縁が面取りされて円錐面となっている。そ
こで、この面取り部分を形成するため、凹部１１１は、
図示の通り、貫通孔１１３側（図示上側）は六角孔、エ
ジェクターピン１０９側（図示下側）は円錐面となる複
雑な形状にくり抜かれていた。このような複雑な形状の
孔は、通常の機械加工によって研削するのは困難であ
り、従来は放電加工によって形成されていた。[0003] By the way, bolt heads and nut blanks
Generally, the top surface periphery is chamfered to form a conical surface. Therefore, in order to form this chamfered portion, the concave portion 111
As shown in the figure, the through hole 113 side (upper side in the figure) was hollowed out into a hexagonal hole, and the ejector pin 109 side (lower side in the figure) was hollowed out into a complicated shape having a conical surface. Holes having such a complicated shape are difficult to grind by ordinary machining, and have conventionally been formed by electric discharge machining.
【０００４】[0004]
【発明が解決しようとする課題】しかしながら、従来技
術によれば、以下に述べるような種々の問題があった。
まず、凹部１１１を放電加工で形成するには、放電加工
用の電極を作成する必要があり、この電極の作成にコス
トがかかっていた。However, according to the prior art, there are various problems as described below.
First, in order to form the recess 111 by electric discharge machining, it is necessary to prepare an electrode for electric discharge machining, and the production of this electrode is costly.
【０００５】また、放電加工は、通常の機械加工に比べ
て加工時間がかかるという欠点もあった。更に、放電加
工を施すと、加工表面に微細な電食痕（クラック）が発
生しやすく、冷間圧造工具では圧造時に強い衝撃を受け
るため、ここからニブの割れが発生するなど、ニブの寿
命が短くなる原因になっていた。[0005] In addition, the electric discharge machining also has a disadvantage that machining time is longer than that of ordinary machining. Furthermore, when electrical discharge machining is performed, fine electrolytic corrosion marks (cracks) are likely to be generated on the machined surface, and a strong impact is generated at the time of forging with a cold forging tool. Was becoming shorter.
【０００６】更にまた、上述のような電食痕を除去する
と共に、表面形状を整えるため、凹部１１１には放電加
工後に入念なラップ仕上げが施されていたが、複雑な形
状なだけにラップ仕上げにも時間がかかり、しかも、ラ
ップ加工には技能工を必要とするといった問題もあっ
た。Further, in order to remove the above-mentioned electrolytic corrosion traces and to adjust the surface shape, the concave portion 111 is carefully wrapped after the electric discharge machining. It takes time, and the lapping process requires a skilled worker.
【０００７】そこで、本発明は、ニブの加工が容易で、
耐用寿命も長い安価な冷間圧造工具を提供することを目
的とする。[0007] Therefore, the present invention provides easy nib processing.
An object of the present invention is to provide an inexpensive cold forging tool having a long service life.
【０００８】[0008]
【課題を解決するための手段，作用，及び効果】上述の
目的を達成するため、本発明は、請求項１記載の通り、
軸方向の端面に所定形状の凹部を有する第１のニブと、
断面形状が多角形となる軸方向への貫通孔を有する第２
のニブとを、前記凹部及び前記貫通孔を連通させる様に
重ねてダイスケースに嵌入し、前記両ニブによって多角
形の機械要素ブランクを冷間圧造するための成形孔を形
成した冷間圧造工具において、前記第１のニブの凹部を
円錐台状に形成すると共に、前記第２のニブの貫通孔の
開口周縁には前記凹部側へ突出する環状の凸部を形成
し、該環状の凸部は、外周面を前記凹部の内周面に密着
する形状とし、内周面を前記貫通孔と同一形状としたこ
とを特徴とする。Means for Solving the Problems, Functions and Effects In order to achieve the above-mentioned object, the present invention provides the following
A first nib having a concave portion of a predetermined shape on an axial end face;
Second having a through hole in the axial direction whose cross-sectional shape is polygonal
A cold forging tool having a nib formed therein for forming a forming hole for cold forging a polygonal machine element blank with the two nibs by overlapping the concave portion and the through hole so as to communicate with each other and fitting the die into a die case. In the method, the concave portion of the first nib is formed in a truncated cone shape, and an annular convex portion protruding toward the concave portion is formed around the opening of the through hole of the second nib. Is characterized in that the outer peripheral surface has a shape that is in close contact with the inner peripheral surface of the recess, and the inner peripheral surface has the same shape as the through hole.
【０００９】本発明の冷間圧造工具によれば、第２のニ
ブの貫通孔の開口周縁には、第１のニブの凹部側へ突出
する凸部が形成されている。この凸部は、第１のニブの
凹部に密着する円錐面からなる外周面と、前記貫通孔を
延長して形成した内周面とで構成され、この凸部が第１
のニブの凹部に入り込み、凸部の外周面と凹部の内周面
とが密着状態で当接すると、凹部の一部が凸部によって
埋められることにより、端部が円錐面で面取りされた多
角柱状の空間、即ち、圧造品の型が形成される。According to the cold heading tool of the present invention, the convex portion protruding toward the concave side of the first nib is formed on the periphery of the opening of the through hole of the second nib. The convex portion includes an outer peripheral surface formed of a conical surface that is in close contact with the concave portion of the first nib, and an inner peripheral surface formed by extending the through hole.
When the outer peripheral surface of the convex portion and the inner peripheral surface of the concave portion are brought into close contact with each other, a part of the concave portion is filled with the convex portion, so that the end portion is chamfered by a conical surface. A columnar space, i.e., a form of a forged product is formed.
【００１０】本発明の冷間圧造工具においては、第１の
ニブには、円錐台状の凹部を形成するだけでよく、ま
た、第２のニブには、円錐台状の凸部を形成し、そこに
多角形の孔を貫通させるだけでよい。したがって、放電
加工を施すことなく、通常の機械加工によってニブを研
削して、所要の形状とすることができる。この結果、従
来品に比べて簡単にニブを製造でき、冷間圧造工具の製
造コストを大幅に下げることができる。In the cold forging tool of the present invention, the first nib need only be formed with a truncated cone-shaped recess, and the second nib is formed with a truncated cone-shaped projection. It is only necessary to penetrate a polygonal hole there. Therefore, the nib can be ground into a required shape by ordinary machining without performing electrical discharge machining. As a result, the nib can be easily manufactured as compared with the conventional product, and the manufacturing cost of the cold forging tool can be significantly reduced.
【００１１】また、ニブには、放電加工特有の電食痕が
発生しないため、ニブそのものの耐用寿命が上がる。こ
の結果、ニブの交換回数が減って圧造機の稼働率も向上
し、機械要素ブランクの生産効率が上がる。ところで、
圧造の際に、空気や機械油などがニブの中に閉じ込めら
れると、パンチングを阻害したり、更には、ニブの破壊
を招いたりする恐れがある。[0011] Further, since the electric erosion mark peculiar to electric discharge machining does not occur in the nib, the service life of the nib itself is prolonged. As a result, the number of times of nib replacement is reduced, the operation rate of the forging machine is improved, and the production efficiency of machine element blanks is increased. by the way,
If air, machine oil, or the like is trapped in the nib during forging, punching may be hindered, and further, the nib may be broken.
【００１２】そこで、請求項２に記載の通り、前記第１
のニブと前記第２のニブとは、前記凹部と前記凸部とで
密着させ、両ニブの互いに対向する端面の間には隙間を
形成するとよい。このように構成すれば、空気や油等
は、第１，第２のニブの間の隙間を通って外部へ逃げや
すくなり、パンチングが阻害されず、ニブの割れ等も防
止され、ニブの寿命が更に延びると期待される。Therefore, as described in claim 2, the first
The nib and the second nib may be brought into close contact with the concave portion and the convex portion, and a gap may be formed between the end faces of the nibs facing each other. According to this structure, air, oil, and the like easily escape to the outside through the gap between the first and second nibs, so that punching is not hindered, the nib is prevented from cracking, and the life of the nib is reduced. Is expected to extend further.
【００１３】更に、請求項３記載の通り、前記第２のニ
ブを、軸心から放射状に延びる分割面によって、それぞ
れが前記貫通孔の壁面となる一つの平面を有する多数の
ニブ小片に分割してもよい。このように構成した冷間圧
造工具によれば、ニブ小片を所要の個数組み合わせれ
ば、各ニブ小片の有する平面が向き合って壁面となり、
多角形の貫通孔を形成する。このニブ小片の加工にあた
っては表面の研削だけで良く、多角形の貫通孔を加工す
る場合に比べると、ニブの製造コストを大幅に下げるこ
とができる。また、圧造による衝撃力によって発生する
ニブの割れは、多角形の角に当たる位置に発生しやすい
が、本発明の冷間圧造工具では、予めニブが分割してあ
るので、予期しない箇所でニブが割れてしまう恐れがな
い。更に、ニブ小片とニブ小片との間から、空気や油を
逃がすことも容易にできる。Further, the second nib is divided into a large number of nib pieces each having one plane which becomes a wall surface of the through hole by a dividing surface extending radially from an axis. You may. According to the cold heading tool configured as described above, if a required number of nib pieces are combined, the planes of the nib pieces face each other to form a wall surface,
Form a polygonal through-hole. Processing of the nib pieces only requires grinding of the surface, and the manufacturing cost of the nibs can be significantly reduced as compared with the case of processing a polygonal through hole. Nib cracks generated by the impact force due to forging are likely to occur at positions corresponding to the corners of the polygon.However, in the cold forging tool of the present invention, the nibs are divided in advance, so that the nibs may be unexpectedly formed. There is no risk of cracking. Further, air or oil can easily escape from between the nib pieces.
【００１４】このように第２のニブを複数のニブ小片に
分割する場合、特に、請求項４記載の冷間圧造工具のよ
うに、前記環状の凸部には、更に、前記分割面によって
分割された部分に隙間を形成しておけば、この隙間から
外部へと空気や油がきわめて逃げやすくなり、ニブの耐
久性をより一層高めることができる。When the second nib is divided into a plurality of nib pieces as described above, the annular convex portion is further divided by the division surface, as in the case of the cold forging tool according to claim 4. If a gap is formed in the set portion, air and oil can very easily escape from the gap to the outside, and the durability of the nib can be further improved.
【００１５】[0015]
【実施例】次に、本発明の実施例を図面に基づいて説明
する。冷間圧造工具１は、図１に示す通り、図示上端面
に凹部３を有する第１のニブ５と、断面形状が六角形の
貫通孔７を有する第２のニブ９とを、凹部３及び貫通孔
７を連通させる様に重ねてダイスケース１０に嵌入し、
第１，第２のニブ５，９によってフランジナットを冷間
圧造するための成形孔を形成している。Next, an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, the cold forging tool 1 includes a first nib 5 having a concave portion 3 on an upper end surface in the drawing and a second nib 9 having a through hole 7 having a hexagonal cross-sectional shape. The through-holes 7 are overlapped so as to communicate with each other, and fitted into the die case 10.
Forming holes for cold forging the flange nut are formed by the first and second nibs 5 and 9.
【００１６】凹部３は、内周面が円錐面にされ、底面に
は図示下方へピン孔１１が貫通している。フランジナッ
トの圧造時には、ピン孔１１はエジェクターピン１３で
塞がれる。第２のニブ９は、図２に示すように、断面形
状が等脚台形となる６つのニブ小片１５からなり、上記
等脚台形の上底となる面１５ａを貫通孔７の壁面となる
様に対向させ、上記等脚台形の脚となる面１５ｂ同士を
接触させ、内周面及び外周面が正六角形となるように組
み合わせて、ダイスケース１０に嵌めてある。The recess 3 has a conical inner peripheral surface, and a pin hole 11 penetrates the bottom surface downward in the figure. When the flange nut is forged, the pin hole 11 is closed by the ejector pin 13. As shown in FIG. 2, the second nib 9 is composed of six nib pieces 15 each having a trapezoidal cross-sectional shape, and a surface 15 a serving as an upper bottom of the trapezoidal shape is a wall surface of the through hole 7. The surfaces 15b, which will be the legs of the above-mentioned isosceles trapezoid, are brought into contact with each other, and the inner and outer peripheral surfaces are combined so as to form a regular hexagon and fitted into the die case 10.
【００１７】貫通孔７の凹部３側の開口周縁には、図１
に示すとおり、凹部３側へ突出する凸部１７が形成され
ている。凸部１７は、外周面が凹部３の内周面に密着す
る形状（即ち、円錐面）とされ、内周面が貫通孔７の壁
面をそのまま軸方向へ延長した面とされ、全体として貫
通孔７を囲んで環状となり、軸方向へは、６つの双曲線
状の稜線を描く山が突出する形状となっている。なお、
貫通孔７の図示上端側の開口１９は、フランジナットの
フランジ部分を形成するため、鍔状に広がっている。The periphery of the opening of the through hole 7 on the side of the recess 3 is shown in FIG.
As shown in FIG. 7, a convex portion 17 protruding toward the concave portion 3 is formed. The convex portion 17 has a shape (i.e., a conical surface) in which the outer peripheral surface is in close contact with the inner peripheral surface of the concave portion 3, and the inner peripheral surface is a surface that extends the wall surface of the through hole 7 in the axial direction as it is, and the entire through hole is penetrated. It has an annular shape surrounding the hole 7, and has a shape protruding in the axial direction, drawing six hyperbolic ridges. In addition,
The opening 19 at the upper end in the drawing of the through hole 7 is formed in a flange shape to form a flange portion of the flange nut.
【００１８】更に、第１のニブ５と第２のニブ９とは、
上記凹部３と上記凸部１７とが、面接触率９９％以上の
密着状態で接触し、一方、図３に拡大して示すように、
第１，第２のニブ５，９の互いに対向する端面の間に
は、隙間２１が形成されている。この隙間２１は、実験
値では最大で幅０．３ｍｍまでに設定すると、空気や油
の抜けが良好で、ニブの寿命も向上することが確認され
た。圧造品の形状や材質などによっては、更に幅を広げ
て、幅０〜１ｍｍ程度の範囲で設定しても良いと考えら
れる。また、各ニブ小片１５に対応して６つに分割され
る凸部１７にも、その分割される部分に隙間２３を形成
してある。この隙間２３は、幅約０．０５〜０．１ｍｍ
とし、図４に示すように、貫通孔７の六角形の６つの角
に当たる位置にそれぞれ設けられている。なお、図４に
おいて、円形に表れる凸部１７の裾部の直径は、貫通孔
７の対角距離の１．１〜１．５倍程度の寸法に設定して
ある。Further, the first nib 5 and the second nib 9
The concave portion 3 and the convex portion 17 come into contact with each other in a state of close contact with a surface contact rate of 99% or more, while, as shown in an enlarged manner in FIG.
A gap 21 is formed between the end faces of the first and second nibs 5 and 9 facing each other. It has been confirmed that when the gap 21 is set to a maximum width of 0.3 mm according to the experimental value, air and oil are well removed and the life of the nib is improved. Depending on the shape and material of the forged product, it is considered that the width may be further increased and set in the range of about 0 to 1 mm in width. In addition, a gap 23 is formed in the divided portion of the projection 17 which is divided into six corresponding to each nib small piece 15. This gap 23 has a width of about 0.05 to 0.1 mm.
As shown in FIG. 4, the through holes 7 are provided at positions corresponding to six corners of a hexagon. In FIG. 4, the diameter of the skirt portion of the convex portion 17 that appears in a circular shape is set to a size that is about 1.1 to 1.5 times the diagonal distance of the through hole 7.
【００１９】このように冷間圧造工具１を構成すれば、
第１，第２のニブ５，９には、いずれも複雑な形状の成
形孔を加工しなくて良く、それぞれ研磨機等による通常
の機械加工で製造することができる。特に、第２のニブ
９については、６つのニブ小片１５を組み合わせて構成
したので、六角孔を形成するための穴ぐり加工も必要と
しない。したがって、穴ぐり加工や放電加工等が必要で
あった従来品に比べて、簡単にニブを製造でき、冷間圧
造工具１の製造コストは大幅に下がる。If the cold forging tool 1 is configured as described above,
Each of the first and second nibs 5 and 9 does not need to form a molding hole having a complicated shape, and can be manufactured by ordinary machining using a grinder or the like. In particular, since the second nib 9 is configured by combining the six nib pieces 15, it is not necessary to perform a boring process for forming a hexagonal hole. Therefore, the nib can be manufactured more easily and the manufacturing cost of the cold heading tool 1 is greatly reduced as compared with a conventional product that requires drilling or electrical discharge machining.
【００２０】また、第１，第２のニブ５，９には、放電
加工特有の電食痕が発生しないため、ニブそのものの耐
用寿命も延びる。この結果、ニブの交換回数が減って圧
造機の稼働率も向上し、フランジナットの生産効率が上
がる。更に、第２のニブ９をニブ小片１５の組合せによ
って構成したので、予期しない箇所でニブが割れる恐れ
がなく、ニブ小片１５とニブ小片１５との間から、空気
や油を逃がすことも容易である。特に、第１，第２のニ
ブ５，９の互いに対向する端面の間には隙間２１を形成
し、また、凸部１７にも６箇所の隙間２３を形成したの
で、これらの隙間２１，２３から外部へ空気や油がきわ
めて逃げやすくなり、ニブの耐久性がより一層高まる。In addition, since the first and second nibs 5 and 9 do not have electric erosion marks peculiar to electric discharge machining, the service life of the nibs themselves is extended. As a result, the number of times of changing the nib is reduced, the operation rate of the forging machine is improved, and the production efficiency of the flange nut is increased. Further, since the second nib 9 is constituted by a combination of the nib pieces 15, there is no possibility that the nib is broken at an unexpected place, and it is easy to allow air or oil to escape from between the nib pieces 15 and the nib pieces 15. is there. Particularly, a gap 21 is formed between the end faces of the first and second nibs 5 and 9 facing each other, and six gaps 23 are also formed in the projection 17. This makes it extremely easy for air and oil to escape to the outside, making the nib more durable.
【００２１】以上本発明の実施例を説明したが、本発明
はこれに限定されず、本発明の要旨を逸脱しない範囲内
の種々なる態様を採用することができる。例えば、実施
例では、フランジナットを圧造するニブを示したが、フ
ランジの無いナットブランクはもちろん、ボルト頭を圧
造する際にも、本発明の冷間圧造工具を採用することが
できる。Although the embodiment of the present invention has been described above, the present invention is not limited to this, and various embodiments can be adopted without departing from the gist of the present invention. For example, in the embodiment, the nib for forging a flange nut has been described. However, the cold forging tool of the present invention can be used for forging a bolt head as well as a nut blank without a flange.
【００２２】また、六角ボルト・ナットに限らず、四角
ボルト・ナットを圧造することもできる。その場合、第
２のニブは４つのニブ小片に分割すると良い。更に、実
施例では第２のニブをニブ小片に分割したが、分割しな
いくても複雑な形状の凹部は無いので、放電加工によら
ず、研磨機による加工が十分に可能である。但し、多角
形の孔を開ける手間、衝撃による割れの防止、あるいは
空気や油等の排出などといった点を考えると、実施例の
ように予めニブを分割する方がより望ましい。Further, not only hexagonal bolts and nuts but also square bolts and nuts can be forged. In that case, the second nib may be divided into four nib pieces. Further, in the embodiment, the second nib is divided into nib pieces. However, even if the second nib is not divided, there is no concave portion having a complicated shape. However, it is more desirable to divide the nibs in advance as in the embodiment in view of the trouble of opening a polygonal hole, prevention of cracks due to impact, and discharge of air and oil.
【図１】 実施例としての冷間圧造工具を一部省略して
示す正面断面図である。FIG. 1 is a front sectional view showing a cold forging tool as an embodiment, with a part thereof omitted.
【図２】 実施例としての冷間圧造工具の平面図であ
る。FIG. 2 is a plan view of a cold heading tool as an example.
【図３】 第１，第２のニブを拡大して示す正面断面図
である。FIG. 3 is an enlarged front sectional view showing first and second nibs.
【図４】 第２のニブを拡大して示す底面図である。FIG. 4 is an enlarged bottom view showing a second nib.
【図５】 従来の冷間圧造工具を示す正面断面図であ
る。FIG. 5 is a front sectional view showing a conventional cold heading tool.
１・・・冷間圧造工具、３・・・凹部、５・・・第１の
ニブ、７・・・貫通孔、９・・・第２のニブ、１０・・
・ダイスケース、１１・・・ピン孔、１３・・・エジェ
クターピン、１５・・・ニブ小片、１７・・・凸部、１
９・・・開口、２１，２３・・・隙間。DESCRIPTION OF SYMBOLS 1 ... Cold heading tool, 3 ... recessed part, 5 ... 1st nib, 7 ... Through-hole, 9 ... 2nd nib, 10 ...
・ Dice case, 11 ・ ・ ・ Pin hole, 13 ・ ・ ・ Ejector pin, 15 ・ ・ ・ Nib small piece, 17 ・ ・ ・ Protrusion, 1
9 ... opening, 21, 23 ... gap.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭55−136537（ＪＰ，Ａ) 特開 昭57−31434（ＪＰ，Ａ) 特開 昭61−38734（ＪＰ，Ａ) 特開 昭58−179531（ＪＰ，Ａ) 特開 昭59−147735（ＪＰ，Ａ) 特開 昭59−1043（ＪＰ，Ａ) 実開 平６−70936（ＪＰ，Ｕ) 実開 平５−78335（ＪＰ，Ｕ) ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-55-136537 (JP, A) JP-A-57-31434 (JP, A) JP-A-61-38734 (JP, A) 179531 (JP, A) JP-A-59-147735 (JP, A) JP-A-59-1043 (JP, A) JP-A-6-70936 (JP, U) JP-A-5-78335 (JP, U)
Claims (4)
第１のニブと、断面形状が多角形となる軸方向への貫通
孔を有する第２のニブとを、前記凹部及び前記貫通孔を
連通させる様に重ねてダイスケースに嵌入し、前記両ニ
ブによって多角形の機械要素ブランクを冷間圧造するた
めの成形孔を形成した冷間圧造工具において、 前記第１のニブの凹部を円錐台状に形成すると共に、前
記第２のニブの貫通孔の開口周縁には前記凹部側へ突出
する環状の凸部を形成し、 該環状の凸部は、外周面を前記凹部の内周面に密着する
形状とし、内周面を前記貫通孔と同一形状としたことを
特徴とする冷間圧造工具。1. A first nib having a concave portion having a predetermined shape on an axial end face, and a second nib having a through hole in an axial direction having a polygonal cross-sectional shape, the concave portion and the through hole. A cold forming tool in which the two nibs form a forming hole for cold forming a polygonal machine element blank, wherein the concave portion of the first nib is conical. In addition to being formed in a trapezoidal shape, an annular convex portion protruding toward the concave portion is formed on the periphery of the opening of the through hole of the second nib, and the annular convex portion has an outer peripheral surface formed on the inner peripheral surface of the concave portion. A cold forging tool characterized in that it has a shape that is in close contact with the through hole, and an inner peripheral surface has the same shape as the through hole.
凸部とで密着させ、両ニブの互いに対向する端面の間に
は隙間を形成したことを特徴とする冷間圧造工具。2. The cold forging tool according to claim 1, wherein the first nib and the second nib are in close contact with each other at the concave portion and the convex portion, and between the opposing end faces of both nibs. A cold forging tool characterized by forming a gap in the tool.
具において、 前記第２のニブを、軸心から放射状に延びる分割面によ
って、それぞれが前記貫通孔の壁面となる一つの平面を
有する多数のニブ小片に分割したことを特徴とする冷間
圧造工具。3. The cold forging tool according to claim 1, wherein the second nib is divided into one plane that becomes a wall surface of the through hole by a divided surface extending radially from an axis. A cold forging tool, wherein the tool is divided into a number of nib pieces.
れた部分に隙間を形成したことを特徴とする冷間圧造工
具。4. The cold forging tool according to claim 3, wherein the annular convex portion further has a gap formed in a portion divided by the dividing surface.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11277894A JP2703725B2 (en) | 1994-05-26 | 1994-05-26 | Cold forging tool |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11277894A JP2703725B2 (en) | 1994-05-26 | 1994-05-26 | Cold forging tool |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07314074A JPH07314074A (en) | 1995-12-05 |
| JP2703725B2 true JP2703725B2 (en) | 1998-01-26 |
Family
ID=14595267
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11277894A Expired - Fee Related JP2703725B2 (en) | 1994-05-26 | 1994-05-26 | Cold forging tool |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2703725B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20000030600A (en) * | 2000-03-08 | 2000-06-05 | 김영옥 | A method of manufacturing a screw which is available for jack |
| CN103551479B (en) * | 2013-07-01 | 2016-01-20 | 江苏森威精锻有限公司 | A kind of Cam bit die |
| CN109175185A (en) * | 2018-08-21 | 2019-01-11 | 湖南铂固标准件制造有限公司 | A kind of method of interior hexagonal cylindrical headdress flower tooth bolt chamfer machining molding die and processing bolt |
-
1994
- 1994-05-26 JP JP11277894A patent/JP2703725B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH07314074A (en) | 1995-12-05 |
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